Revenue from Contracts with Customers Financial Statement Impact of Adopting ASC 606 (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	$ 198,632	$ 213,897	$ 221,666	$ 213,256	$ 199,477	$ 205,683	$ 197,010	$ 168,487
Income (loss) from operations									$ 9,889	$ (179,864)	$ 31,780
Inventories	$ 118,722				$ 120,925				$ 118,722	$ 120,925